1. Field of the Invention
This invention relates to an automatic mask (reticle) washing apparatus for the production of semiconductor integrated circuits (IC), and in particular, to cleaning a mask without the use of a strong oxidizing agent or strong alkaline agent.
2. Description of the Prior Art
In semiconductor device manufacturing, it is important to obtain a clean surface mask in order to attain high reliability of devices and high yield of production. There are apparatuses to clean the slices or substrates of semiconductors, but cleaning of the mask is done by hand. The reason the masks have been cleaned manually is that the number of masks used in the process is much smaller than that of the slices. But as the scale of production increases and the complexity of the IC is increased, the number of masks used in the process has become large.
The contamination or damage to the mask is due to the dust, mist, finger masks, spit, etc. In order to remove such contamination, hard washing is not desirable. Moreover, strong oxidizing or alkaline agents are also undesirable because of straining of the mask surface. The cleaning of the mask by hand has not been satisfactory and, therefore, apparatuses for washing and drying of the mask are beginning to be used.
By the experience of the inventor herein, it is insufficient to use prior art apparatuses for washing, drying and so on because during transportation between stages of the apparatus, the mask surface is exposed to the air and thus, contaminated. It is desirable, therefore, to use an apparatus which handles the mask automatically from loading the mask, washing, drying and taking out.